固氪物态方程的关联量子化学计算  

Equation of state of solid krypton from correlated quantum chemistry calculations

作　　者：武娜[1] 杨皎[1] 肖芬[1] 蔡灵仓[2] 田春玲[1] 

机构地区：[1]西南大学物理科学与技术学院,重庆400715 [2]中国工程物理研究院流体物理所,绵阳621900

出　　处：《物理学报》2014年第14期266-271,共6页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2011CB808201);重庆市自然科学基金(批准号:CSTC2009BA4005)资助的课题~~

摘　　要：运用多体展开理论和量子化学方法—–超分子单、双(三重)激发微扰处理耦合簇CCSD(T)方法,首次系统地计算了面心立方固氪在较宽(从晶格平衡位置到体积压缩率超过3倍)区间的两体、三体和四体相互作用对结合能和物态方程的贡献大小,包括Hartree-Fock自洽场项和范德瓦耳斯长程关联作用项;并与实验数据进行比较.结果表明,在考虑到两体、三体、四体相互作用能后,多体展开理论以及CCSD(T)方法对平衡位置结合能测量数据0—130 GPa整个研究区间的实验物态方程数据都做出令人满意的描述.The two-, three- and four-body interaction energies in face-centered cubic（fcc） krypton are evaluated using the many-body expansion method and the coupled cluster theory with full single and double excitations plus perturbative treatment of triples, and both self-consistent-field（SCF） Hartree-Fock energy and correlation one are accurately determined in a wide volume range（from 27 to 4 cm3/mol）. All different three- and four-atom clusters existing in the first three and two nearest and two neighbor shells of fcc lattice are considered. It is found that the three-body interaction energy is positive at low compression, where the dispersive forces play a dominant role, with increasing the compression the three-body contribution becomes attractive, and the SCF energy overwhelms the dispersive one. At pressures higher than 30 GPa, the four-body contribution becomes important and significantly cancels the over-softening effects of the three-body potential. It shows that the combination of the four-body effects with two- and three-body interactions leads to an excellent agreement with the measurements from the equation of state in the whole experimental range of0–130 GPa.

关 键 词：结合能 CCSD(T)方法 物态方程 固氪 

分 类 号：O413[理学—理论物理]